Trump, drawn into duels with Cruz, didn't back down, calling the Texan's comments about New Yorkers "insulting" at one point. Trump still spoke for a significant segment of the debate, sticking to a steady routine of interruptions without getting tested too seriously.

Yet late in the debate, Trump's presence dissipated slightly, opening a spot for Marco Rubio, who used his increased time to take on Cruz, who he sparred with most frequently in the previous debate.

Halfway through Thursday's slugfest it appeared Rubio would be mostly shunned by his opponents, but he used an almost two-minute segment to air a litany of Cruz's flip-flops on immigration, which Cruz parried.

The final count had Cruz speaking the most for the third straight debate, finishing at 18 minutes and three seconds. Trump came in second with 17 minutes and 8 seconds. Rubio spoke for just over 14 minutes. The ever-muted Ben Carson finished last, speaking for just eight minutes and 25 seconds.